jeffrey.kissel@LIGO.ORG - posted 14:54, Friday 21 July 2017 - last comment - 11:50, Friday 28 July 2017(37689)
ETMs Checked for Rubbing with Top-to-Top Mass TFs -- Appear Clear
J. Kissel
Performed same check on ETMs as I did yesterday on ITMs with standard Top Mass to Top Mass transfer functions.
I similarly attach sneak peak screenshotss of fully processed data, but having watched the TFs go by,
The ETMs are clear of rubbing.
Left to do: all 10 of the triples, 3 doubles, and if we really care, the 9 singles.
(PS, we should get these as reference anyways, in prep for the up-coming vent)
Please ignore the difference with the black references on the reaction chains -- to save time, rather than figure out good templates for the ETMs, I copied over the ITM template and replaced the characters ITM with ETM. We know that ITM reaction chains have different resonance shapes and frequencies that the ETM reaction chains. From years of staring at these, I can tell they're fine. Again, will process these later to show how they really compare what's expected.
The main chains between ETMs and ITMs are identical, so their comparison can be treated as legit.
Data is stored and committed to svn here:
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMX/SAGM0/Data/
2017-07-21_2004_H1SUSETMX_M0_WhiteNoise_L_0p01to50Hz.xml
2017-07-21_2004_H1SUSETMX_M0_WhiteNoise_P_0p01to50Hz.xml
2017-07-21_2004_H1SUSETMX_M0_WhiteNoise_R_0p01to50Hz.xml
2017-07-21_2004_H1SUSETMX_M0_WhiteNoise_T_0p01to50Hz.xml
2017-07-21_2004_H1SUSETMX_M0_WhiteNoise_V_0p01to50Hz.xml
2017-07-21_2004_H1SUSETMX_M0_WhiteNoise_Y_0p01to50Hz.xml
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMX/SAGR0/Data/
2017-07-21_2051_H1SUSETMX_R0_WhiteNoise_L_0p01to50Hz.xml
2017-07-21_2051_H1SUSETMX_R0_WhiteNoise_P_0p01to50Hz.xml
2017-07-21_2051_H1SUSETMX_R0_WhiteNoise_R_0p01to50Hz.xml
2017-07-21_2051_H1SUSETMX_R0_WhiteNoise_T_0p01to50Hz.xml
2017-07-21_2051_H1SUSETMX_R0_WhiteNoise_V_0p01to50Hz.xml
2017-07-21_2051_H1SUSETMX_R0_WhiteNoise_Y_0p01to50Hz.xml
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMY/SAGM0/Data/
2017-07-21_2005_H1SUSETMY_M0_WhiteNoise_L_0p01to50Hz.xml
2017-07-21_2005_H1SUSETMY_M0_WhiteNoise_P_0p01to50Hz.xml
2017-07-21_2005_H1SUSETMY_M0_WhiteNoise_R_0p01to50Hz.xml
2017-07-21_2005_H1SUSETMY_M0_WhiteNoise_T_0p01to50Hz.xml
2017-07-21_2005_H1SUSETMY_M0_WhiteNoise_V_0p01to50Hz.xml
2017-07-21_2005_H1SUSETMY_M0_WhiteNoise_Y_0p01to50Hz.xml
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMY/SAGR0/Data/
2017-07-21_2055_H1SUSETMY_R0_WhiteNoise_L_0p01to50Hz.xml
2017-07-21_2055_H1SUSETMY_R0_WhiteNoise_P_0p01to50Hz.xml
2017-07-21_2055_H1SUSETMY_R0_WhiteNoise_R_0p01to50Hz.xml
2017-07-21_2055_H1SUSETMY_R0_WhiteNoise_T_0p01to50Hz.xml
2017-07-21_2055_H1SUSETMY_R0_WhiteNoise_V_0p01to50Hz.xml
2017-07-21_2055_H1SUSETMY_R0_WhiteNoise_Y_0p01to50Hz.xml
Images attached to this report
Comments related to this report
More detailed plots of ITMX, compared against previous measurements and model. Both Main and Reaction chains show expected dynamics and are clear of rubbing.
Non-image files attached to this comment
More detailed plots of ITMY, compared against previous measurements and model. The reaction chain checks out OK. This latest main chain's data set (2017-07-20) resolution is at 0.02 Hz instead of the previous measurement which was at the standard 0.01 Hz -- so it *looks* like some resonances are truncated, but upon close inspection, they're just not resolving the resonance. Not sure what happened during the (main chain) pitch measurement at high frequency, but this behavior has been present in the 2017-04-25 and 2017-01-17 data sets. The last clean undamped data set is way back in 2014-10-28; there is a 2.5 year gap in the data for this chain... so difficult to say. From my experience, I propose is that the main chain is OK too, given that data points surrounding the resonances match up nicely for all other DOFs. However, while I finish out the single / double rubbing checks (or during yet another earthquake) I'll remeasure the main chain with a high resolution and focus on getting a good pitch measurement.
Non-image files attached to this comment
More detailed plots of ETMX. I'm 10% suspicious about the main chain (M0) and reaction (R0) chain showing their first two L 2 L resonances a little stunted since these were last measured on 2014-12-22, but this may just be due to lack of coherence. But, as with ITMY above, the data points surrounding the resonances all line up nicely. My yellow flag trigger is twitchy, likely because this is the suspension with one of the worst BSC ISI ST2 longitudinal coupling (see LHO aLOG 37752). All other dynamics check out... Further investigation is needed here (sheesh).
Non-image files attached to this comment
More detailed plots of ETMY, compared against previous measurements and model. Both Main and Reaction chains show expected dynamics and are clear of rubbing.
Non-image files attached to this comment
Because we're also considering TOP Mass flags moving around (not big enough to cause rubbing, but enough to cause (a) a moment of inertia change and therefore resonant frequency change, or (b) a change in cross-coupling to non-diagonal response to diagonal drive, e.g. L to P, or V to L, etc), I also post the individual transfer functions for each QUAD, and a previous measurement against which to compare. I've taken a look through all of these, and they don't show much difference. If anything, the new transfer functions just show a more coherent TF because I've improved the drive parameters to get better SNR. Cross-coupling plots start on pg 7 of each attachment.
Non-image files attached to this comment